PhD Program in Rehabilitation Sciences, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL, USA.
School of Physical Therapy, Marshall University, Huntington, WV, USA.
Hum Mov Sci. 2021 Dec;80:102890. doi: 10.1016/j.humov.2021.102890. Epub 2021 Nov 5.
The predictability of perturbation magnitude plays an important role in control of standing posture. The aim of the study was to examine anticipatory (APAs) and compensatory (CPAs) postural adjustments in response to catching objects of uncertain mass. Twenty adults caught the same object with either light or heavy weight placed in it. Electromyographic activity of eight trunk and leg muscles, displacements of the center of pressure, and angular displacement of the shoulder joint were recorded and analyzed during the APAs and CPAs intervals. When the subjects experienced repeated catching of the object with the same weight, they estimated the object mass beforehand and generated APAs more precisely. When the object mass changed unpredictably, they generated APAs based on the most recent catch and needed four to six trials to optimize APAs and CPAs. The muscle co-contraction was a primary pattern for catching the object of uncertain mass. The results of the study suggest that catching the object of uncertain mass is a challenging task that involves co-contraction of postural muscles to maintain balance.
扰动幅度的可预测性在站立姿势控制中起着重要作用。本研究的目的是检验对不确定质量物体的捕捉的预期（APAs）和补偿（CPAs）姿势调整。二十名成年人用轻或重的物体来捕捉同一个物体。在 APA 和 CPA 间隔期间，记录和分析了八个躯干和腿部肌肉的肌电图活动、压力中心的位移以及肩关节的角位移。当参与者反复用相同重量捕捉物体时，他们会事先估计物体的质量，并更准确地产生 APA。当物体的质量不可预测地变化时，他们会根据最近的一次捕捉产生 APA，并且需要四到六次试验来优化 APA 和 CPA。肌肉协同收缩是捕捉不确定质量物体的主要模式。研究结果表明，捕捉不确定质量的物体是一项具有挑战性的任务，需要协同收缩姿势肌肉来保持平衡。
